The present invention relates to an arrangement for the step-by-step height adjustment of a holding or deflecting fitting of a seat belt on a hollow body part of a motor vehicle, particularly on a B-column or C-column, having a guide rail mounted on the body part, and a carriage which can be displaced along the guide rail, can be fixed in defined adjusting positions and has a fastening device for the holding or deflecting fitting, and in which the guide rail, which is arranged behind a column covering, is mountable on the vehicle body part by means of two mutually spaced fastenings.
Arrangements of the initially mentioned type, which are usually called belt height adjusting devices, are used for adapting the height of the deflecting or fastening point of a seat belt to the body size of a vehicle occupant to be protected. In four-door passenger cars, the belt height adjusting arrangements are normally mounted in the upper part of the B- and C-columns. For adjusting the height of a fitting, usually by pressure onto a cover cap of a screw connecting the holding or deflecting fitting with the carriage, a carriage is pressed against the force of a spring in the direction of the column, in order to release the fixing caused by mutual detent engagement of detent elements of the carriage and of a guiding rail, so that the carriage can be moved along the guide rail into the desired adjusting position. When the cover cap is subsequently relieved from pressure, the detent elements again enter into a mutual detent engagement, so that the carriage is held in the selected adjusting position.
Many such arrangements are known from the prior art. Reference is made, for example, to German Patent Document DE 198 22 696 A1.
There is a risk that a motor vehicle occupant's head will carry out a transverse motion and impact on an area in which the deflecting fitting is arranged when lateral forces act upon a vehicle equipped with the deflecting fitting in the event of an accident, for example. In this case, loads which are above a permissible limit value may act upon the vehicle occupant's head.
It is known from German Patent Document DE 197 19 572 A1 to arrange a deformation element, which is designed for absorbing energy in the event of pressure admission to the seat belt linkage point, between the seat belt linkage point and the vehicle body part. Viewed in the transverse direction of the vehicle, such a deformation element requires a relatively large amount of additional space.
It is known from German Patent Document DE 196 15 804 C2 to arrange a damping device between the adjusting part holding the deflecting fitting and the vehicle body part at which a rail is fastened or can be fastened. When impact-caused forces act upon the deflecting fitting, the damping device is supported on the adjusting part and the vehicle body part and can be deformable during the process for damping impact energy. A corresponding space has to be provided for housing such a damping device.
It is an object of the invention to further develop a fastening for a belt height adjusting arrangement according to the above-mentioned type such that, in the event of a head impact onto the holding or deflecting fitting, loads acting upon the vehicle occupant's head are below the permissible limit value.
According to the invention, this object is achieved by having the guide rail and therefore an entire belt height adjusting arrangement, while absorbing energy, be laterally swivellable, starting from a defined force level, about an axis of rotation, formed by one of two fastenings of the guide rail and extending in the transverse direction of the vehicle, upon impact of a vehicle occupant's head with the holding or deflecting fitting. Additional characteristics advantageously further developing the invention are defined by the dependent claims.
Principal advantages achieved by the invention are that, in the event of a head impact onto the holding or deflecting fitting at a defined force level, the belt height adjusting arrangement, while absorbing energy, can be laterally swivelled about an axis of rotation formed by one of the two fastenings of the carrier rail and extending in the transverse direction of the vehicle. Energy is absorbed during swivelling of the belt height adjusting arrangement, and thus the head loads occurring are below the permissible limit value. Furthermore, an additional energy absorption can take place by deformation of the column covering disposed in front.
In one embodiment, the belt height adjusting arrangement swivels about the upper fastening, and specifically, viewed from the vehicle occupant compartment, against the driving direction toward the rear. Thus, while absorbing energy, the belt height adjusting arrangement yields laterally in the longitudinal direction of the vehicle. Energy absorption is formed by a bent-away column-side lug which bends or deforms during the swivelling of the guide rail of the belt height adjusting device. As a result of the geometry of the lug (length, width, thickness, set angle), the force level can be defined, starting from which the lug bends during the swivelling of the guide rail.
The invention will be explained in detail in the following by means of an embodiment illustrated in the drawing.